Wire drawing lubricant containing a diamide, hydrated lime, and a normal calcium soap



United States Patent Patented- Oct. 11, 1960 William Maurice Franks, Rockfall, Conan, assignor to Nopco Chemical Company, Harrison, N.J., a, corporation of New Jersey No Drawing. Filed Apr. 13, 1956, SeruNo. 577,937

8 Claims. (Cl. 252-18) This invention relates to the drawing of steel wire. More particularly, it relates to novel lubricating compositions which are well suitedfor use in such processes.

The use of lubricating compositions is a technique well known and widely practiced in the wire drawing art. Lubricating compositions are employed in wire drawing operations for several reasons. One of the foremost of these is to facilitate the drawing or reduction of the wire to the size desired. However, in addition to this, a lubricant is used in the dry drawing of wire to increase the effective life of the dies through which the wire is drawn by protecting them from excessive wear. The wire drawing lubricant accomplishes these desired objectives by providing suflicient lubrication to maintain a low coefficient of sliding friction between the surface of the wire and the surface of the die through which the wire is drawn.

Many compositions have been suggested for use as lubricants in the dry drawing of steel wire. Heretofore, compounds, such as, clay, alumina, talc and boric acid have been employed in the industry as wire drawing lubricants. In addition, compositions, such as, mixtures of ferrous sulfate with anhydrous water-soluble soaps; mixtures of sulphur with metallic stearates; mixtures of tricresyl phosphate with calcium or aluminum soaps of oxidizedpetroleum oils; andmixtures of hydrated lime with aluminum stearate; as well as sulphurized fatty oils; chlorinated naphthalenes; etc., have been employed. The use of soda base soaps has also found wide application in the wire drawing processes of the art.

While many of the compositions proposed in the art as wire drawing lubricants have. been satisfactory ,in some respects, such products were not always completely satisfactory. In many instances, the proposed lubricant did not facilitate to any great extent. the wire drawing operations. Using many of the prior art compositions, it was not possible to achieve a sufficiently great reduction in the size of the wire per draw. As a result, a finished product ofv desired size could be obtained often, only by drawing the wire through a greater number of drawing dies than is desirable or practical. Moreover, many of the compositions of the art did not sufficiently reduce the coefiicient of sliding friction between the surface of the wire and the surface of the dies. As a result, the dies were subjected to excessive wear and the surface finish of the wire was unsatisfactory. Many wire drawing lubricants proposed in the. art possessed properties and characteristics, other than. those discussed above, which rendered them impractical or unsuitable. for use in industrial operations.

Itis the object of this invention to provide compositions which are well suited for use as lubricants in the dry drawing of steel wire.

It is a more particular object of the invention to furnish wire drawing lubricants'which facilitate the drawing operation and, hence, permit a wire to be drawn to any particular size using a'lesser number of drawing dies than might otherwise be required using the conventional lubricants of the art.

It is a further object of the invention to provide a wire drawing lubricant which maintains a relatively low co:- efficient of sliding friction between the surface 'of the wire being drawn and the surface of the die through which it is drawn.

Other objects of the invention will be obvious. and will, in part, appear hereinafter.

It has been discovered that the objects of the invention can be achieved, in industrial wire drawing operations, by the use of a lubricant which comprises an intimate admixture of a high calcium content composition;

the exact nature of which will be described hereinafter, and a wax or a wax like material.

The high calcium content compositions which are employed in producing the novel wire drawing lubricants of the invention arebest described as compositions comprising lime and normal calcium soaps of certain fatty acids. These compositions are produced at elevated temperatures by mixing hydrated lime with a suitable fatty acid. The hydrated lime is employed in quantities which are in excess of the amount theoretically required to produce the normal calcium soap of the fatty acid present. The precise manner in which the fatty acid and the hydrated lime are reacted to produce the high calcium content composition is not a part of, and hence does not limit either the scope or the practice of, the invention. In general, a product of the type described herein, produced by any method known in the art, is completely suitable for use in the production of the wire drawing lubricants of theinvention. However, the composition can be obtained very readily by mixing the fatty acid component and the hydrated lime, in an aqueous-slurry, at a temperature of from about C. to about C. When carried out in this manner, it has been found that the reaction of thefatty acid and the hydrated lime will be greatly facilitated by the use of relatively small quantities of an alkaline catalyst, as, for example, 0.1% by weight of potassium hydroxide, based upon the weight of the fatty acid component in .use.

The fatty acid employed in the production of the high calcium content compositions which are used in the practice of the invention, can be varied. In general, any saturated aliphatic monocarboxylic acid having a carbon chain length of from about 12 to about 18 carbon atoms can be used. Specifically, fatty acids which are offered to the trade as laur'ic acid, myristic acid, palmitic acid and stearic acid can be employed. It will be immediately evident to those skilled in the art that such commercially available saturated fatty acids are not pure chemical compounds. Rather, they are mixtures which contain fatty acids, both saturated and unsaturated. I The aver age molecular Weights of these mixtures approximate the theoretical molecular weights of'lauric acid, myristic acid, palmitic acid or stearic acid.' Such commercial fatty acids can be, and are, usedin producing the'hig'li calcium content compositions that are employed herein. In addition, however, the high calcium content composi tions which are used in producing the wire drawing lubri cants of the invention can be prepared from the natural mixtures of fatty acids such as are obtained from hydrogenated glycerides. The only restriction on the use of such mixtures is that they must contain predominanlt pro portions of saturated fatty acids having carbon chain lengths of from 12 to 18 carbon atoms. Thus, for ex ample, high calcium content compos'itions'producedfrom the natural fatty acids obtained from hydrogenated-tal low, hydrogenated coconut oil; hydrogenated soybean oil, etc., can be used in the production-of thefhig'h calcium content compositions which are employed in practiceof/the invention. a

As disclosed heretofore, the high calcium content compositions which are used in producing the novel wire drawing lubricants are prepared by reacting a fatty acid or fatty acid mixture with hydrated lime. The high calcium content of these compositions is attained by the use of quantities of lime in their production which are in excess of the quantity required to produce the normal calcium soap of the particular fatty acid. In its broadest embodiment, the invention contemplates the use of high calcium content compositions containing a quantity of hydrated lime, the weight of which is from about 35% to about 65% by weight of the total weight of the high calcium content composition. The fatty acid portion of the high calcium content composition employed in the preferred embodiment of the invention is composed of the natural mixtures of fatty acids derived from hydrogenated tallow, and the quantity of hydrated lime is from about 45% to about 55% by weight of the total weight of the high calcium content composition. In producing the wire drawing lubricants of the invention, the high calcium content composition is admixed at room temperature with either a wax or with a waxlike composition. The expression wax-like composition is used herein to connote materials which, although they have all of the physical characteristics of a wax, technically are not waxes. In general, any wax or any waxlike material having a melting point above 130 C. can be employed. Particularly well suited for use, however, are diamides produced by reacting ethylene diamine with saturated, aliphatic monocarboxylie acids having carbon chain lengths of from 12 to 18 carbon atoms. Among these are the diamides of ethylene diamine and lauric acid, m'yristic acid, palmitic acid and stearic acid as well as diamides of ethylene diamine and the natural mixtures of fatty acids derived from hydrogenated glycerides, such as, coconut oil, soybean oil, etc. The preferred products of the invention contain a diamide produced from ethylene diamine and hydrogenated tallow fatty acids as the wax-like component. However, in addition to such diamides of the ethylene diamine, other comparable waxes or wax-like materials, as, for example, natural or synthetic waxes or hydrogenated glycerides which have melting points above 130 C., can be employed.

For best results, the wax or wax-like material used should be comminuted or ground or otherwise reduced to a finely divided form prior to mixing with the high calcium content composition. While the size of the individual particles thereof is not a particularly critical aspect of the invention, the wax or wax-like component of the product should have a particle size Which at least I,

approximates that of the high calcium content composition with which it is to be admixed. When the particles of each component of the product are comparable in size, the possibility of physical separation of the respective ingredients in the finished product, as, for example, during transit, will be reduced to an absolute minimum. It has been found that completely satisfactory results are obtained when a wax or wax-like material, ground through a round hole screen, is employed.

Neither the use of special equipment nor a knowledge of new techniques is required to produce the novel wire drawing lubricants of the invention. The method by which the lubricants are prepared is readily adapted to commercial scale production. Thus, the finely divided wax-like material is ordinarily added to the dry, powdery high calcium content composition. Since, however, the order of addition is immaterial to the operability of the invention, the high calcium content composition can be added to the finely divided wax-like component. The ingredients are, thereafter, mixed thoroughly at room temperature. Mixing can be accomplished either manually or by suitable mechanical means. However, irrespective of the manner in which the mixing operation is carried out, the ingredients of the product should be mixed sufiiciently well to obtain a relatively homogeneous mix. The finished product will be dry and powdery.

In producing the novel lubricants of the invention, the ingredients thereof are admixed in such proportions that the high calcium content component comprises from about to about 95% of the weight of the finished product. The finely divided wax or wax-like material comprises from about 5% to about 15% of the weight of the finished product. In producing the preferred products of the invention, the high calcium content composition and the finely divided wax-like material are compounded in such proportions that the high calcium content composition comprises about and the finely divided wax-like material about 10% of the total weight of the finished product.

The products of the invention can be employed in the conventional dry drawing processes of the art. No changes whatsoever either in the equipment or techniques used in the industry are occasioned by the use of the present products. Thus, for example, in a typical dry drawing process, wire is drawn in continuous and successive stages through a series of drawing dies. The aperture of each die in the series is smaller than that of the die immediately preceding. A die box, containing the wire drawing lubricant, is positioned in the line prior to the first die and, ordinarily, between each succeeding die in the series. Thus, in the usual process, the wire is passed through a die box and, hence, lubricated prior to each draw. The properties of the products of the present invention are such that they are well suited for use in such processes.

Several distinct advantages accrue from the use of the lubricant compositions of the invention in the dry drawing of steel wire. Thus, for example, the lubricity that the products of the invention impart to steel wire during dry drawing is comparable, if not superior, to that provided by many of the most satisfactory wire drawing lubricants of the art. As a direct result of this, maximum reduction in the size of the wire per draw is attainable. This characteristic, of course, permits a wire to be drawn or reduced to a given size using fewer drawing dies than might otherwise have been required. Furthermore, since the products of the invention furnish steel wire with greatly enhanced lubricity, quite often it will be unnecessary to lubricate the wire prior to drawing it through each die in the series. Moreover, since the products of the invention, by virtue of their superior lubricating properties, greatly reduce the coetficient of sliding friction between the surface of the wire and the surface of the dies through which it is drawn, the wire obtained when they are used as the lubricant has a completely satisfactory surface finish. In addition, due to the enhanced lubricity and the resulting low coefiicient of sliding friction provided by the present products, the drawing dies are protected against undue and excessive wear. In this manner, the effective life of the die is prolonged.

Moreover, the products of the present invention obviate in many instances certain difficulties encountered in the use of the conventional products of the art. For one thing, when using the products of the invention in the conventional dry wire drawing process, inadequate lubrication of the wire caused by the channeling 0f the wire through the lubricant in the die box is less likely to occur. Moreover, by using the present products, the drawn wire is free of the sticky or tacky residue frequently encountered when many products of the prior art were used. The presence of such residues materially hinders the handling of the finished product.

For a fuller understanding of the nature and objects of this invention, reference may be had to the following example which is given merely as a further illustration of the invention and is not to be construed in a limiting sense.

Example Ninety parts by weight of a high calcium content composition and 10.0 parts by weight of a synthetic wax-like material were intimately admixed at room temperature until visual examination of the mass revealed it to be a homogeneous mixture.

The high calcium content composition used herein was a product produced by agitating about 46.1 parts by weight of the fatty acids derived from hydrogenated tallow and about 56.83 parts by weight of hydrated lime in 140 parts by weight of water at a temperature of about 85 C. Reaction between these materials was facilitated by adding 0.05 part by weight of flaked potassium hydroxide to the reaction mixture. Water was removed from the paste-like product thus obtained and the dry, high calcium content composition thus produced was thereafter pulverized.

The synthetic wax-like material employed was a product produced by reacting about 95.7 parts by weight of the fatty acids of hydrogenated tallow with 15.3 parts by weight of ethylene diamine (70%). The product obtained by this reaction was ground in a micropulverizer using a A inch round hole screen.

The product of the example was evaluated as a wire drawing lubricant in an industrial wire drawing establishment under actual service conditions. It was used as the lubricant on galvanized steel wire which was subjected to one die reduction from 0.112 inch to 0.104 inch. The product was adjudged to be completely satisfactory for use as a wire drawing lubricant. It facilitated the reduction of the wire, adequately protected both the surface of the wire and the surface of the drawing die from excessive wear and left no tacky residue on the surface of the finished wire.

Having described the invention what I claim is new and desire to secure by Letters Patent is:

1. A wire drawing lubricant consisting essentially of a dry mixture of from about to about by weight of a diamide having a melting point above about 130 C., said diamide being the reaction product of ethylene diamine and a saturated aliphatic monocarboxylic acid having a carbon chain length of from about 12 to about 18 carbon atoms, and from about 85% by weight to about 95% by weight of a high calcium content composition comprising hydrated lime and a normal calcium soap of a saturated aliphatic monocarboxylic acid having a carbon chain length of from about 12 to about 18 carbon atoms, the hydrated lime comprising from about 35% to about 65% of the total weight of said high calcium content composition.

2. A wire drawing lubricant consisting essentially of a dry mixture of from about 5% to about 15% by weight of a diamide having a melting point above about 130 C., said diamide being the reaction product of ethylene 6 diamine and a saturated aliphatic monocarboxylic acid having a carbon chain length of from about 12 to about 18 carbon atoms, and from about to about by weight of a high calcium content composition comprising hydrated lime and a normal calcium soap of a saturated aliphatic monocarboxylic acid having a carbon chain length of from about 12 to about 18 carbon atoms, the hydrated lime comprising about 45% to about 55% of the weight of the high calcium content composition.

3. A wire drawing lubricant consisting essentially of a dry mixture of about 10% by weight of a diamide having a melting point above about C., said diamide being the reaction product of ethylene diamine and a saturated aliphatic monocarboxylic acid having a carbon chain length of from 12 to about 18 carbon atoms, and about 90% by weight of a high calcium content composition comprising hydrated lime and the normal calcium soap of hydrogenated tallow fatty acids, the hydrated lime comprising about 45% to about 55% of the weight of the high calcium content composition.

4. The composition of claim 3 wherein the diamide is the reaction product of ethylene diamine and lauric acid.

5. The composition of claim 3 wherein the diamide is the reaction product of ethylene diamine and myristic acid.

6. The composition of claim 3 wherein the diamide is the reaction product of ethylene diamine and palmitic acid.

7. The composition of claim 3 wherein the diamide is the reaction product of ethylene diamine and stearic acid.

8. The composition of claim 3 wherein the diamide is the reaction product of ethylene diamine and hydrogenated tallow fatty acids.

References Cited in the file of this patent UNITED STATES PATENTS 1,948,194 Williams Feb. 20, 1934 1,963,298 Elder June 19, 1934 2,152,396 Williams Mar. 28, 1939 2,251,092 Williams July 29, 1941 2,251,093 Williams July 29, 1941 2,294,535 Burwell Sept. 1, 1942 2,319,393 Epstein May 18, 1943 2,334,076 Epstein Nov. 9, 1943 OTHER REFERENCES Handbook of Material Trade Names, Zimmerman et al., Industrial Research Service, Dover, N.I-I., page 209 (1946). 

1. A WIRE DRAWING LUBRICANT CONSISTING ESSENTIALLY OF A DRY MIXTURE OF FROM ABOUT 5% TO ABOUT 15% BY WEIGHT OF A DIAMIDE HAVING A MELTING POINT ABOVE ABOUT 130* C., SAID DIAMIDE BEING THE REACTION PRODUCT OF ETHYLENE DIAMINE AND A SATURATED ALIPHATIC MONOCARBOXYLIC ACID HAVING A CARBON CHAIN LENGTH OF FROM ABOUT 12 TO ABOUT 18 CARBON ATOMS, AND FROM ABOUT 85% BY WEIGHT TO ABOUT 95% BY WEIGHT OF A HIGH CALCIUM CONTENT COMPOSITION COMPRISING HYDRATED LIME AND A NORMAL CALCIUM SOAP OF A SATURATED ALIPHATIC MONOCARBOXYLIC ACID HAVING A CARBON CHAIN LENGTH OF FROM ABOUT 12 TO ABOUT 18 CARBON ATOMS, THE HYDRATED LIME COMPRISING FROM ABOUT 35% TO ABOUT 65% OF THE TOTAL WEIGHT OF SAID HIGH CALCIUM CONTENT COMPOSITION. 